Backup Crew

Flight

The launch was originally
planned for mid October 1992. Technical problems with one of the main engines
forced the
NASA to replace it. This work was done on the launch
pad.

Primary mission objectives were the deployment of the Laser
Geodynamic Satellite II (LAGEOS II) and the operation of the U.S.
Microgravity Payload-1 (USMP-1).

The Laser Geodynamics
Satellite (LAGEOS) II, like its predecessor launched in 1976,
was a passive satellite dedicated exclusively to laser ranging. Laser ranging
involves sending laser beams from Earth to the satellite and recording the
round-trip travel time. This measurement enables scientists to precisely
measure the distances between laser ranging stations on the Earth and the
satellite.LAGEOS was designed to provide a reference point for
laser ranging experiments that monitored the motion of the Earth's crust,
measure and understand the "wobble" in the Earth's axis of rotation, collected
information on the Earth's size and shape and more accurately determined the
length of the day. The information was particularly useful for monitoring
regional fault movement in earthquake-prone areas such as California and the
Mediterranean Basin.The
LAGEOS II project is a joint program between
NASA and the Italian space agency
ASI.

The
LAGEOS II satellite was a spherical satellite made of
aluminum with a brass core. It was only 24 inches (60 cm) in diameter yet it
weighed approximately 900 pounds (405 kg). This compact, dense design made the
satellite's orbit as stable as possible.The
LAGEOS design evolved from several trade-offs that
proved necessary to achieve the program objectives. For example, the satellite
had to be as heavy as possible to minimize the effects of nongravitational
forces, yet light enough to be placed in a high orbit. The satellite had to be
big enough to accommodate many retroreflectors, but small enough to minimize
the force of solar pressure.LAGEOS II had the dimpled appearance of a large golf
ball. Imbedded into the satellite are 426 nearly equally spaced, cube-corner
retroreflectors, or prisms. Most of the retroreflectors (422) are made of
suprasil, a fused silica glass. The remaining four, made of germanium, may be
used by lasers of the future. About 1.5 inches (3.8 cm) in diameter, each
retroreflector had a flat, circular front-face with a prism-shaped back.The
retroreflectors on the surface of
LAGEOS II were three-dimensional prisms that reflected
light, in this case a laser beam, directly back to its source. A timing signal
started when the laser beam leaves the ground station and continues until the
pulse, reflected from one of
LAGEOS II's retroreflectors, returned to the ground
station.

After the Shuttle released under the lead of Tamara
Jernigan on flight day 2
LAGEOS II, two solid-fuel stages, the Italian Research
Interim Stage (IRIS) and the
LAGEOS Apogee Stage (LAS), engaged. The IRIS boosted
LAGEOS II from the Shuttle's 184-mile (296 km) parking
orbit to the satellite injection altitude of 3,666 miles (5,900 km). The LAS
circularized the orbit. This was the first IRIS mission and qualified the IRIS,
a spinning solid fuel rocket upper stage, for use in deploying satellites from
the Space Shuttle cargo bay.LAGEOS II's circular orbit was the same as that of
LAGEOS I, but at a different angle to the Earth's
equator: 52 degrees for
LAGEOS II and 110 degrees for
LAGEOS I. The complementary orbit provided more
coverage of the seismically active areas such as the Mediterranean Basin and
California, improving the accuracy of crustal-motion measurements. It also may
help scientists understand irregularities noted in the position of
LAGEOS I, which appear to be linked to erratic
spinning of the satellite itself.

The USMP program was a series of
NASA missions designed for microgravity experiments
that do not require the "hands-on" environment of the Spacelab.The
USMP-1 payload carried three investigations. The
Lambda-Point Experiment (LPE) studied fluid behavior in microgravity. The
Materials for the Study of Interesting Phenomena of Solidification on Earth and
in Orbit, (Materiel pour l'Etude des Phenomenes Interessant la Solidification
sur Terre et en Orbite, or MEPHISTO) studied metallurgical processes in
microgravity. The Space Acceleration Measurement System (SAMS) studied the
microgravity environment onboard the Space Shuttle.Two Mission-Peculiar
Equipment Support Structures (MPESS) in the Shuttle cargo bay made up
USMP-1. Carrier subsystems mounted on the front MPESS
provided electrical power, communications, data-handling capabilities and
thermal control.
MSFC
developed the
USMP
carrier.

The Lambda-Point Experiment (LPE) studied liquid helium
as it changes from normal fluid to a superfluid state. In the superfluid state,
helium moves freely through small pores that block other liquids, and it also
conducts heat 1,000 times more effectively than copper. This change occurs at
liquid helium's "lambda point" (-456 degrees Fahrenheit or 2.17 degrees
Kelvin). Because the transition from one phase to another causes the organized
interaction of large numbers of particles, it is of great scientific
interest.The transition from fluid to superfluid state could studied more
closely in microgravity than on Earth. Gravity caused a sample of liquid helium
to have greater pressure at the bottom than at the top, in turn causing the top
of the sample to become superfluid at higher temperatures.Onboard
USMP, a sample of helium cooled far below its lambda
point was placed in a low-temperature cryostat (an apparatus used to keep
something cold, such as a thermos bottle). During a series of 2-hour runs
controlled by an onboard computer, the helium's temperature was raised through
the transition point by a precision temperature- control system. Sensitive
instruments inside the cryostat measured the heat capacity of the liquid helium
as it changes phases. The temperature of the helium sample was maintained to
within a billionth of degree during the experiment.

Materials for the
Study of Interesting Phenomena of Solidification on Earth and in Orbit
(MEPHISTO) was a joint American-French cooperative program. The definition
and development of the flight hardware has been led by
CNES (French Space Agency) and CEA (French Atomic
Energy Commission).MEPHISTO studied the behavior of metals and
semiconductors as they solidify to help determine the effect gravity has during
solidification at the point where solid meets liquid, called the solid/liquid
interface. Data gathered from MEPHISTO were used to improve molten materials.
For example, more resilient metallic alloys and composite materials could be
designed for engines that will power future aircraft and spacecraft.The
cylindrical-shaped MEPHISTO furnace experiment contained three identical
rod-shaped samples of a tin-bismuth alloy. MEPHISTO will process the samples
using two furnaces, one fixed and one moving. As a run begins, the mobile
furnace will move outward from the fixed furnace, melting the samples. The
mobile furnace then moved back toward the fixed furnace, and the sample
resolidifies. The fixed furnace contained a stationary solid/liquid interface
to be used as a reference for studying the mobile solid/liquid
interface.MEPHISTO has been designed to perform quantitative investigations
of the solidification process by using several specific diagnosis methods.
During the experiment runs, a small electrical voltage constantly measured the
temperature changes at the interface to verify solidification rates. During the
last experimental run, electrical pulses were sent through one sample,
"freezing" the shape of the interface for post-mission analysis.The
MEPHISTO apparatus allowed many cycles of solidification and remelting and was
particularly welladapted for long-duration missions. During the mission,
scientists compared the electrical signal to data from a SAMS sensor to see if
the Shuttle's movement is disturbing the interface. They then could make
adjustments to the experiments if necessary. Post-mission analysis of the
space-solidified sample allowed correlation between the electrical measurements
and changes in the sample.

The Space Acceleration Measurement System
(SAMS) was designed to measure and record low-level acceleration during
experiment operations. The signals from these sensors were amplified, filtered
and converted to digital data before it was stored on optical disks and sent
via downlink to the ground control center.USMP-1
was the first mission for two SAMS flight units in the cargo bay configuration.
The two units each supported two remote sensor heads. Two heads were mounted in
the Lambda Point Experiment (LPE) and the other two heads were mounted to the
MPESS structure near the MEPHISTO furnace.SAMS flight hardware was designed
and developed in-house by the
NASA Lewis Research Center and Sverdrup Technology
Inc. project team. The units have flown on STS-40, STS-43,
STS-42,
STS-50 and
STS-47 missions.

The Attitude
Sensor Package (ASP) experiment consisted of three unique spacecraft
attitude sensors, an on board computer and a support structure. The primary
sensor was the Modular Star Sensor (MOSS). The other two sensors were the Yaw
Earth Sensor (YESS) and the Low Altitude Conical Earth Sensor (LACES). The ASP
sensors and their support structure were assembled on a Hitchhiker small
mounting plate. The Hitchhiker avionics, mounted to another small mounting
plate, provided power and signal interfaces between the ASP experiment and the
Shuttle.Often the performance of the space instruments cannot be predicted
accurately on Earth because of the lack of knowledge of and actual simulation
of the space environment. The ASP experiment exposed these attitude sensors to
actual space conditions, demonstrating their performance and accuracy. This
flight experience was evaluated by
ESA for
possible use of these sensors on future
ESA
programs.

Canadian Experiments-2 (CANEX-2)
was a group of space technology, space science, materials processing and life
sciences experiments which were performed in space by Canadian Payload
Specialist Steven
MacLean during the
STS-52 mission of Space Shuttle Columbia. Bjarni
Tryggvason was a backup crew member and alternate to Steven
MacLean for this mission.The potential applications of
CANEX-2
space research included machine vision systems for use with robotic equipment
in space and in environments such as mines and nuclear reactors. Other
potential applications related to the manufacturing of goods, the development
of new protective coatings for spacecraft materials, improvements in materials
processing, a better understanding of the stratosphere which contains the
protective ozone layer, and greater knowledge of human adaptation to
microgravity.Many of these experiments are extensions of the work carried
out by Marc
Garneau as part of the
CANEX
group of experiments that helped form his 1984 mission (STS-41G).The development of the Space Vision System
(SVS), a machine vision system for robotic devices, such as the Canada arm,
was undertaken to enhance human vision in the unfavorable viewing conditions of
space. The SVS could provide information on the exact location, orientation and
motion of a specified object. Steven
MacLean evaluated an experimental Space Vision System for
possible use in the Space Shuttle and in the construction of Space Station
Freedom.For the
CANEX-2
experiments, target dots have been placed on the Canadian Target Assembly
(CTA), a small satellite carried in the Space Shuttle's cargo bay. During the
flight, a mission specialist used the arm to deploy the CTA and take it through
a series of maneuvers using the information displayed by the SVS. Steven
MacLean evaluated SVS performance and investigated details
that need to be considered to design a production model of the
system.

The Materials Exposure in Low-Earth Orbit (MELEO)
experiment was an extension of work performed by the
CSA
which began with the Advanced Composite Materials Experiment (ACOMEX) flown on
Marc Garneau's 1984 mission. Researchers now wanted to extend the
valuable baseline date obtained to further investigate the deterioration
process, try new protective coatings and test materials designed for use on
specific space hardware such as the Mobile Servicing System (MSS) for the Space
Station Freedom and RADARSAT, the Canadian remote sensing satellite scheduled
for launch in early 1995.The MELEO experiment exposed over 350 material
specimens mounted on "witness plates" on the Canada arm and analyzed after the
mission. Typical spacecraft materials were tested along with new developments
in protective measures against atomic oxygen. The specimens were exposed in the
flight direction for at least 30 hours. Steven
MacLean periodically photographed the specimens to record the
stages of erosion. All materials were returned to Earth for detailed
examination.The experiments included Orbiter Glow-2 (OGLOW-2), Queen's
University Experiment in Liquid-Metal Diffusion (QUELD), Sun Photo Spectrometer
Earth Atmosphere Measurement (SPEAM-2), Phase Partitioning in Liquids (PARLIQ),
Space Adaptation Tests and Observations (SATO), Vestibular-Ocular Reflex Check,
Body Water Changes in Microgravity, Illusions During Movement.

Tank
Pressure Control Experiment/Thermal Phenomena (TPCE/TP) represented an
extension of the data acquired in the Tank Pressure Control Experiment (TPCE)
which flew on STS-43 in 1991. The flight
of TPCE significantly increased the knowledge base for using jet-induced mixing
to reduce the pressure in thermally stratified subcritical tanks. Mixing
represents a positive means of limiting pressure build-up due to thermal
stratification and may allow non-vented storage of cryogenics for some of the
shorter duration missions.The purpose of the reflight, TPCE/TP, was to
focus on the thermal phenomena involved in the selfpressurization of
subcritical tanks in a low-g environment.

Physiological Systems
Experiment-02 (PSE-02) evaluated a compound being developed to treat
osteoporosis. The experiment tested the ability of the compound to slow or stop
bone loss induced by microgravity. Scientists examined whether the lower
gravity experienced on a space flight accelerates the rate at which bone mass
is lost, compared to losses observed when a limb is immobilized on Earth.In
this experiment, six healthy, adolescent, male, albino rats were treated with
the Merck developmental anti-osteoporotic compound prior to flight. An
equivalent number of flight rats remained untreated to serve as controls. The
two groups were housed in completely self- contained units called Animal
Enclosure Modules (AEMs) during the flight. The AEMs contained enough food and
water for the duration of the mission. No interaction with the crew was
required on orbit. A clear plastic cover on the AEM permitted the crew to
visually inspect the condition of the rats.The Heat Pipe Performance (HPP)
experiment on
STS-52 evaluated the sensitivity of state-of-the-art
heat pipes to large and small accelerations. It also gathered data on the force
needed to 'deprime' (dry out) heat pipes and how long it takes them to
recover.During the mission, the astronauts assembled HPP in the orbiter's
middeck area and conducted the tests. Four heat pipes were evaluated in each
experiment run by rotating them on a cross-shaped frame. A motor on an
instrument unit mounted to the middeck floor drove the assembly. A
battery-powered data logger recorded the data.

The Shuttle Plume
Impingement Experiment (SPIE) recorded measurements of atomic oxygen and
contamination from Shuttle thruster firings during
STS-52.With sensors located at the end of
Columbia's mechanical arm, SPIE supported the
CANEX-2
MELEO experiment as it exposed materials to the atomic oxygen in the vicinity
of Columbia. During these operations, the mechanical arm was positioned to
place the SPIE sensor package in the direction of travel of Columbia, and the
atomic oxygen levels were recorded on a portable computer in the Shuttle
cabin.

The objective of the Commercial Programs is sponsoring the
Commercial MDA ITA Experiments (CMIX) payload was to provide industry and CCDS
users with low-cost space experimentation opportunities, thereby supporting one
of the objectives of the
NASA CCDS program to provide commercial materials
development projects that benefit from the unique attributes of space.The
goal of the protein crystal growth experiments was to produce larger, more pure
crystals than can be produced on Earth. The pharmaceutical industry will use
such crystals to help decipher the structure of a protein using X-Ray
crystallographic analysis. The principal commercial application of such data is
in the development of new drugs or treatments.

The Crystal Vapor
Transport Experiment (CVTE) experiment was important to the semiconductor
industry because the ability of semiconductors to process and store information
is dependent on the quality of the crystals used. Thus, large, uniform crystals
grown in space may lead to greater speed and capability of computers, sensors
and other electronic devices.Thermal convection is turbulence induced by
variations in densities caused by the temperature differences that occur in a
material when it's heated. Buoyancy and sedimentation is a similar phenomenon,
created by Earth's gravitational pull, that makes less dense materials rise
(buoyancy) and denser materials sink (sedimentation). Because of these
gravity-induced phenomena, crystals grown on Earth are smaller and less
ordered, containing imperfections that limit the capability of transistors,
sensors and other types of electronic devices.

The Commercial Protein
Crystal Growth (CPCG) goal was to develop the technology and applications
needed for successful space-based protein crystal growth (PCG).Structural information gained from CPCG
activities can provide, among other information, a better understanding of the
body's immune system, and ultimately aid in the design of safe and effective
treatment for disease and infections. For these reasons, CPCG crystal structure
studies were conducted on 7 Shuttle missions starting in 1988.

The
Ultraviolet Plume Experiment (UVPI) was an instrument on the Low-Power
Atmospheric Compensation Experiment (LACE) satellite launched by the Strategic
Defense Initiative Organization in February 1990. LACE was in a 43-degree
inclination orbit of 290 n.m. (537 km). Imagery of Columbia's engine firings or
attitude control system firings were taken on a non-interference basis by the
UVPI whenever an opportunity was available during the
STS-52 mission.